What was found
(CAN) UPON TAXI TO PARKING, GROUND CREWS NOTICED THE NR 1 MAIN WHEEL WAS MISSING. UPON FURTHER INVESTIGATION, IT WAS DISCOVERED THAT THE NR 1 AXLE HAD SHEARED OFF, ALLOWING THE WHEEL TO DEPART THE A/C. THE WHEEL WAS FOUND JUST OFF OF THE TAXIWAY STILL ATTACHED TO THE BROKEN PIECE OF AXLE. THE CREW WAS UNAWARE OF A PROBLEM UNTIL THEY SHUTDOWN THE AIRCRAFT AND DEPLANED. THE LOWER SHOCK STRUT ASSEMBLY WAS REPLACED AND THE AIRCRAFT RETURNED TO SERVICE.